The present invention relates to an ink tank for supplying ink to a print head, and to a recording apparatus with employment of this ink tank.
Conventionally, as the ink supply mechanism employed in the recording apparatus for recording by ink, as described in, for example, Japanese Laid-open Patent Application No. 63-87242, and U.S. Pat. No. 5,025,271, such an ink supply mechanism has been proposed that the porous member is arranged within the ink tank, one end of this porous member is coupled via the filter to the print head, and the other end thereof is provided with the air intake port. In the ink supply mechanism described in this publication, compression force is given to the foam corresponding to the porous member within the vessel by the tab. However, such an arrangement has a problem that the capillary force of the foam would be increased at the depression unit of the foam by the tab, and the ink may readily remain in the foam. Also, there is a design limitation such that to apply the proper compression force, the above-described arrangement could not be realized unless the ink dipped member per se is the elastic member.
Another conventional technique is described in, for instance, Japanese Patent Publication No. 5-23954. That is, in this ink tank, the projection portion is formed which constitutes the space between the inner wall surface of the ink tank and the ink dipped member. Furthermore, this ink tank includes means for communicating this space with the atmosphere. However, when the space is formed by the projection unit, the capillary vessel force of the ink dipped member would be similarly increased at the contact point between the projection unit and the ink dipped member. Thus, there is another problem that the ink may readily remain in the ink dipped member.
Furthermore, Japanese Laid-open Patent Application No. 6-15837 discloses the means having the projection portion around the atmospheric communication port in order that the ink does not dip into the atmospheric communication port. However, also in this case, the capillary vessel force of the porous member would be increased at the contact point between the projection portion and the ink-dipped porous member. Thus, there is a problem that the ink may readily remain in the porous material. Moreover, the porous member concaving with the projection portion may easily form the unwanted space between the inner wall surface of the ink tank and therewith. Accordingly, there is a risk to release negative pressure in the ink tank.